@article{ref1,
title="The development of direct and indirect aggressive strategies: gender differences during ages 8, 11, 15, and 18",
journal="Aggressive behavior",
year="1991",
author="Bjorkqvist, Kaj and Lagerspetz, KMJ and Kaukiainen, K",
volume="17",
number="2",
pages="60-60",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0096-140X",
doi="",
url="http://dx.doi.org/"
}